A new treatment for Alzheimer’s has not been approved for use in the United States since 2003 and the EU since 2002. There is still no cure.

But experts say more drugs than ever are being developed, with 18 per cent more being tested in clinical trials this year than last.

Some 7 per cent more are in final-stage tests.

George Vradenburg, from campaign group UsAgainstAlzheimer’s, said: “The Alzheimer’s disease pipeline, marred by decades of failures and underinvestment, is due for big victories.

“Thanks to growing investment from industry leaders, we remain cautiously optimistic that the current crop of late-stage Alzheimer’s innovations will bring much-needed solutions to families in the near future.”

Dr David Morgan, from the University of South Florida, said: “There is no silver bullet when it comes to treating Alzheimer’s.